Lumidigm Reads Skin Physiology

In addition to obvious differences in skin pigmentation, each person’s skin is structurally unique. Skin layers vary in thickness, interfaces between skin layers have different undulations and other characteristics, collagen fibers and elastic fibers in the skin layers differ, and capillary bed density and location differ. Cell size and density within the skin layers, as well as in the chemical makeup of these layers, also vary from person to person.

Lumidigm propriety hardware and software recognize these skin differences and the optical effects they produce. Lumidigm sensors illuminate a small (0.4 inch diameter) patch of skin with multiple wavelengths (“colors”) of visible and near infrared light. The light that is reflected back after being scattered in the skin is then measured for each of the wavelengths. The changes to the light as it passes through the skin are analyzed and processed to extract a characteristic optical pattern that is then compared to the pattern on record or stored in the device to provide a biometric authorization.

Because the optical signal is affected by changes to the chemistry and other properties of human skin, it also provides a very sensitive and easy way to confirm that a sample is living human tissue. Non-human tissue or synthetic material has very different optical properties than human skin, which cause a corresponding change to the resulting optical signal. Likewise, excised or amputated tissue undergoes rapid changes in biochemistry, temperature and distribution of fluids within the various physiological compartments that also alter the appearance of the sensor signal. These optical differences ensure that a sample authorized by a Lumidigm sensor is truly that of a living human.

For more information on the technology, download the white paper Multispectral Sensing for High-Performance Fingerprint Biometric Imaging (pdf, 537k).

For more information about Lumidigm, please contact us.

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